Second-hand smoke tied to memory problems, study suggests

Smokers and people who regularly breathe others' cigarette fumes are worse at remembering things on their to-do lists than are people with no tobacco exposure, a small study says.

Problems with so-called prospective memory may not only lead to embarrassment if a person forgets to meet with their friends, British researchers write in the journal Addiction. It can also have more-serious consequences such as forgetting to take your medication.

The study doesn't prove that smoke damages memory, but is nonetheless a cause for concern, the researchers say.

"This research extends what is already known about the effects of smoking and second-hand smoke, suggesting there is not only health effects from it, but cognitive consequences too," said Tom Heffernan, the study's lead author from Northumbria University at Newcastle-upon-Tyne.

Heffernan and his colleague recruited 27 current smokers, 24 people who reported regular exposure to second-hand smoke and 28 people who said they were never exposed to smoke, whether first- or secondhand. All were between 18 years old and 30 years old.

The researchers had each person complete the Cambridge Prospective Memory Test, which included time-based tasks, such as returning a key to the researchers when seven minutes were left on the clock, and event-based tasks such as handing over the key when a certain word was said.

Each person received points for the tasks they completed depending on how many prompts the researchers had to give them. Total scores ranged from zero to 18 points for each test, with higher scores meaning better memory.

For the time-based activities, there was a statistically reliable difference between the scores of each group.

People without any exposure to tobacco smoke scored 16.3 points on average, while those who breathed second-hand smoke scored 13.7 points and smokers scored 11.6 points.

For event-based activities, the smoke-free students again did better than smokers, but only marginally better than those exposed regularly to second-hand smoke.

Exactly what the findings mean in real life, and what's responsible for them, is unclear. And while the study suggests there is a link between smoking and memory problems, Heffernan warns that these are results from just one study.

"I think we need to confirm these findings using other methods," he told Reuters Health.